Combustion-powered, fastener-driving tools, such as combustion-powered, nail-driving tools and combustion-powered, staple-driving tools, are exemplified in Nikolich U.S. Pat. No. Re. 32,452, Nikolich U.S. Pat. No. 4,522,162, and No. 4,483,474, Wagdy U.S. Pat. No. 4,483,473, and Nikolich U.S. Pat. No. 4,403,722.
Typically, such a tool includes switches that must be closed to enable ignition of a combustible fuel in a combustion chamber by means of a spark plug. These switches include a head switch and a trigger switch. The head switch is closed by pressing a workpiece-contacting element, which is operatively mounted to a nosepiece of the tool, firmly against a workpiece. The trigger switch is closed by pulling a trigger, which is operatively mounted to a handle of the tool.
An ignition system for such a tool, employing such head and trigger switches, is disclosed in Rodseth et al. U.S. Pat. No. 5,133,329. The ignition system disclosed therein employs photoelectric head and trigger switches, as disclosed in Rodseth U.S. Pat. No. 5,191,209.
A fuel system for such a tool, employing a fuel injector including a solenoid and an electronic circuit for controlling the solenoid to enable a combustible fuel to flow from a source into the combustion chamber for a time interval after the head switch or the trigger switch is closed, is disclosed in a copending patent application filed Nov. 13, 1992, for FUEL SYSTEM FOR COMBUSTION-POWERED, FASTENER-DRIVING TOOL, and assigned commonly herewith.
As disclosed in the copending application noted above, the time interval is defined by a resistive-capacitive network including a thermistor responsive to ambient temperature, along with a resistor arranged to be selectively connected to condition the system for use at higher altitudes and disconnected to condition the system for use at lower altitudes. As disclosed therein, the fuel system can be well integrated with an ignition system according to Rodseth et al. U.S. Pat. No. 5,133,329 noted above.
In such a tool, as known heretofore, a fan has been employed to produce turbulence in the fuel mixing with air in the combustion chamber. Also, a battery-powered, electric motor has been employed to drive the fan. Since the fan and the electric motor are large contributors to the weight of such a tool and to its manufacturing cost, it would be highly desirable to provide such a tool that could be effectively operated without a fan driven by an electric motor.